Question:medium

Two independent random variables X and Y have variances 0.2 and 0.5 respectively. Let Z = 5X - 2Y. The variance of Z is

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Remember that the variance of a difference is not the difference of the variances.
Because coefficients are squared, we have $\text{Var}(aX - bY) = a^2\text{Var}(X) + b^2\text{Var}(Y)$.
The negative sign becomes positive.
Updated On: Jul 7, 2026
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The Correct Option is B

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